Protection Engineering Basics and Schemes Protection Engineering | Page 195
6.1 Differential Protection Relay:
Why we need differential relay?
Some selected equipment / units need to be protected separately from whole power system, as the characteristics of these selected Equipments / units are different from other associated electrical accessories.
� Transformers � Generators � Motors � Busbars Are some specific Equipments / units on which differential relay is employed.
Differential relay is work on simple principle
Electrical Quantities enter in power system = Electrical Quantities exit from power system
We compare magnitude and phase or magnitude or phase of electrical quantities in differential protection relaying.